Measurement and diagnosis of the tear film of an eye is increasingly important for understanding the corneal condition prior to any surgery or therapy. This information may be used to guide surgery, screen patients or provide appropriate drops or other treatment and in diagnosis of dry eye condition.
A great deal of research has been directed toward methods diagnosing dry eye condition and for measuring tear film or tear film breakup in human eyes. “Methodologies to Diagnose and Monitor Dry Eye Disease: Report of the Diagnostic Methodology Subcommittee of the International Dry Eye Work Shop (2007),” 5 THE OCCULAR SURFACE No. 2, April 2007, pp. 108-152 provides a summary of dry eye diagnosis approaches, including slit lamp examination, video recording, and osmolarity analysis. These approaches require a variety of instruments and are sometimes subjective.
Objective measurements of data related to tear film breakup may be analyzed to diagnose dry eye condition. Issues related to such diagnosis include what data should be measured, how the data should be processed for analysis, and what metrics should be employed to gauge the level of tear film breakup for diagnosing a possible dry eye condition.
U.S. Pat. No. 9,504,376, “Optical diagnosis using measurement sequence,” issued on 28 Nov. 2016 to Daniel R. Neal et al., and incorporated herein by reference, describes the use of wavefront aberrometry measurement data to evaluate tear film breakup, as does U.S. patent application Ser. No. 15/343,037, filed on 3 Nov. 2016, and also incorporated by reference herein. For example, U.S. Pat. No. 9,504,376 describes how Wavefront Fit Error (WFFE) and wavefront irregularity may be employed to assess potential tear film break up. Additionally, Haixia Liu et al., “Measurement of the Time Course of Optical Quality and Visual Deterioration during Tear Break-Up,” 51 INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE No. 6, June 2010, pp. 3318-26 describes some optical metrics of tear quality and retinal image quality which are associated with the decline in vision that occurs with tear film breakup. In particular, Liu et al. describe the use of RMS fit error of wavefront data obtained from wavefront aberrometry measurements as a metric for deterioration of visual quality due to tear film breakup during blink suppression. Further, Nikole L. Himebaugh et al., “Scale and Spatial Distribution of Optical Aberrations Associated with Tear Break-up,” 89 OPTOMETRY & VISUAL SCIENCE No. 11, November 2012, pp. 1590-1600, concluded that tear film breakup caused by blink suppression may manifest itself as a combination of wavefront aberrations on macroscopic and microscopic scales due to non-uniform tear film thinning and possible exposure of a rough epithelial surface. Each of these documents is incorporated herein by reference.
However, improved methods and systems of measuring data related to tear film breakup, improved systems and methods of processing measured data related to tear film breakup, and improved metrics for quantifying and evaluating tear film breakup based on such measured and processed data are needed.
Accordingly, it would be desirable to provide new systems and method for measuring tear-film breakup.